高温作用下花岗岩的脆延性转化温度点

Temperature of brittle-ductile transition of granite under high temperature

为了探讨在高温作用下花岗岩的脆延性转化温度点,进行了高温力学试验和扫描电镜试验,分析了温度对花岗岩屈服应变、破坏应变、延性系数和应力-应变关系的影响。试验结果表明:在实时高温作用下及高温作用冷却后花岗岩的脆延性转化温度点均在800℃左右,此时花岗岩晶体中出现穿晶裂纹、解理台阶、滑移带和浅表韧窝等共存特征,岩样呈现延性破坏特征;随着温度的升高,花岗岩破坏方式由突发式的脆性破裂逐渐向渐进式的半脆性剪切破坏转化。

In order to probe the temperature of brittle-ductile transition of granite under high temperature, high-temperature mechanical experiments and SEM experiments were conducted. The influence of temperature on the yield strain, the failure strain, the ductility factor, and the stress-strain curves of granite was also analyzed. The test resuhs show that the temperature of brittle-ductile transition of granite under high temperature or after the high temperature cools is about 800℃. In the meantime, there occurs some coexistence of transerystalline cracks, the cleavage step, the slip band, and superficial dimple in granite crystal and the granite presents characteristics of ductile failure. With the rise of temperature, the failure form of granite changes from abrupt brittle fractures to gradual semi-brittle shear fractures.